Here's a scenario we've seen before: Microsoft leverages its domination of the operating system to muscle its way into an adjacent space. Most of the time, that's a bad thing, leading to the disappearance of smaller, more innovative competitors. The company has been rightfully slapped around for that sort of monopolistic behavior by both U.S. and European regulators.

But when it comes to desktop security -- where Microsoft recently began offering free antimalware software via Microsoft Update -- Microsoft deserves kudos, not slaps. Ironically, Microsoft may be doing consumers and IT a favor by taking on Symantec and its lumbering, customer-unfriendly line of Norton security products.

Symantec, which has huge market share and is often the default security program placed on PCs by manufacturers, has taken its customers for granted for years. Shocking as it may seem, Microsoft may be coming to the rescue.

Microsoft's automatic security downloadMicrosoft Security Essentials (MSE), a perfectly serviceable antimalware application, has always been available free of charge, but compared to paid offerings by Symantec, McAfee, and Trend Micro, its user base of about 30 million is paltry. However, our buddies in Redmond have made it an option in Microsoft Update, which means that users could download and install it with a couple of clicks and no particular thought.

Symantec and Trend Micro have been pretty quiet about this, repeating the usual platitudes about how their products offer much more than the basic protection users get from MSE, how signature-based defenses are too limited, and so on. Security vendors have every right to compete on that basis, and if consumers would rather pay for their products, so be it. In fact, there is some truth to their arguments, and I wouldn't say that MSE is the superior product. But that's not the point.

Trend Micro, though, has taken a more aggressive public stance and is waving the antitrust flag. I'd bet that Symantec and McAfee are also burning lots of billable hours with their attorneys, waiting to see how this unfolds before pulling out the knives.

"Commercializing [Microsoft] Update to distribute other software applications raises significant questions about unfair competition" is what Carol Carpenter, the general manager of the consumer and small business group at Trend Micro, told Computerworld.